Table 1.
Kinetic parameters of N. europaea ADP-Glc PPase for Mg2+, Mn2+, Co2+, and Cd2+a
| Metal ion | Vmax (U/mg) | S0.5 (mM) | nH | kcat/S0.5 (mM−1 · s−1) |
|---|---|---|---|---|
| Mg2+ | >50 | >40 | ND | ∼4 |
| Mn2+ | 52 ± 2 | 1.37 ± 0.05 | >3 | 126 ± 7 |
| Co2+ | 26.45 ± 0.05 | 0.46 ± 0.02 | >3 | 192 ± 8 |
| Cd2+ | 34 ± 5 | 0.74 ± 0.06 | >3 | 150 ± 30 |
a
The reaction mixture had the standard composition except for Cd2+, in which case it contained 2 mM instead of 1 mM Glc-1P. Only points corresponding to the ascending activity (from zero to the maximal) in Fig. 2 were used for data fitting. ND, not determined.